theorem Th24:
for
A,
B,
C,
D being
category st
A,
B are_opposite &
C,
D are_opposite holds
for
F,
G being
covariant Functor of
B,
C st
F,
G are_naturally_equivalent holds
((dualizing-func (C,D)) * G) * (dualizing-func (A,B)),
((dualizing-func (C,D)) * F) * (dualizing-func (A,B)) are_naturally_equivalent